Windows drive letters are not limited to A-Z
7 comments
·November 30, 2025the_mitsuhiko
> In other words, since RtlDosPathNameToNtPathName_U converts C:\foo to \??\C:\foo, then an object named C: will behave like a drive letter. To give an example of what I mean by that: in an alternate universe, RtlDosPathNameToNtPathName_U could convert the path FOO:\bar to \??\FOO:\bar and then FOO: could behave like a drive letter.
For some reason I remember that the original xbox 360 had "drive letters" which were entire strings. Unfortunately I no longer have access to the developer docs and now I wonder if my mind completely made this up. I think it was something like "Game:\foo" and "Hdd0:\foo".
Tanoc
Anybody who's had to look through files on multi-disc arrays knows exactly how weird the drive letters can get. Mount the ISOs of thirty six 8.5GB DVDs because someone thought it was a good idea to split zip a single archive into 7.99GB segments and things get very tricky in cmd. If you weren't in the habit of using several layers of quotation marks to separate everything you'll form it very quickly because the operators can be the same symbols as the drive letters, as shown in the article with the "+" example.
RobotToaster
> Drives with a drive-letter other than A-Z do not appear in File Explorer, and cannot be navigated to in File Explorer.
Well there goes my plan to replace all my drive letters with emojis :(
azalemeth
This all sounds like a wonderful way to write some truly annoying malware. I expect to see hidden mounts on SQL-escape-type-maliciously-named drives soon...
nunobrito
This was a cool article. Learned something new today.
rado
Windows drive letters are ridiculous. Use an external drive for e.g. video editing, its letter can be stolen by another drive, you can’t work anymore.
The cursedness of "€:\" is awesome. It's amazing how much more flexible the NT kernel is vs what's exposed to the user.